1. Field of the Invention
The present invention relates to a lens unit.
2. Description of the Related Art
As a lens unit, for example a fisheye lens unit, suitable for incorporation into an image pickup apparatus or the like having a small image pickup device, there has been known a fisheye lens unit having a total of four lenses, as for examples disclosed in Japanese Patent Laid-open No. 2005-227426 (hereinafter referred to as Patent Document 1).